US4144839A - Feeding device for supplying developer powder to a magnetic drum - Google Patents

Feeding device for supplying developer powder to a magnetic drum Download PDF

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Publication number
US4144839A
US4144839A US05/832,670 US83267077A US4144839A US 4144839 A US4144839 A US 4144839A US 83267077 A US83267077 A US 83267077A US 4144839 A US4144839 A US 4144839A
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US
United States
Prior art keywords
developer powder
drum
magnet
magnet drum
developing apparatus
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05/832,670
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English (en)
Inventor
Werner Salger
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Lumoprint Zindler KG and Co GmbH
Original Assignee
Lumoprint Zindler KG and Co GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Lumoprint Zindler KG and Co GmbH filed Critical Lumoprint Zindler KG and Co GmbH
Application granted granted Critical
Publication of US4144839A publication Critical patent/US4144839A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/09—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer using magnetic brush

Definitions

  • the present invention relates to a developing apparatus for developing a particularly electrostatically generated latent image, the apparatus including a developer powder brush moving on a magnet drum and adapted to be moved contactingly past a latent image-bearing material, particularly of a drum-shaped configuration, whereby the tips of the brush come into relative engagement with this material, and means for conveying developer powder for feeding to the magnet drum.
  • An additional magnet drum rotating within the supply of developer powder brings about the drawback of compressing the surface of the powder in forming a trench having a compressed surface from which the transfer of powder is impeded.
  • centrifugal pump consisting of a conical upwardly and outwardly flaring member.
  • centrifugal force not only provides for the upward feed but likewise effects an enrichment of the developing substance of fluid and particles upon discharge, due to the different specific weights.
  • a pump of this type is advantageous for a fluid developer whereby it may also be assumed that such a fluid developer spreads automatically within a developer trough and will rise communicatingly within the conical member when being delivered by the pump.
  • the object of the present invention to eliminate these drawbacks and to solve the respective problems by providing a novel and improved developing apparatus of the type as stated in the introductory paragraph of the present specification wherein with simplified feed means at the magnet drum there will be generated an even developer powder brush along the length of the magnet drum, substantially simplifying the design of the apparatus.
  • a baffle sheet approaching the periphery of the magnet drum is associated therewith, and that there is provided at least one drivable pump for projecting the developer powder onto this baffle sheet.
  • the design of the means as a pump for projecting the developer powder onto the baffle sheet already constitutes a particularly advantageous arrangement whereby likewise the combination of the baffle sheet approaching the periphery of the magnet drum provides the pre-requisite for establishing, prior to the transfer of the developer powder into the magnet brush, a zone acting as a developer powder reservoir.
  • a baffle sheet end portion disposed below the magnet drum includes an upwardly bent portion against which may accumulate developer powder.
  • a bead-like reservoir zone extending along the axial length of the magnet drum and supplied by the pump, and from which the magnet drum ultimately derives the necessary material for establishing the developer powder brush.
  • an advantageous characteristic is that the spacing of the baffle sheet from the magnet drum at the adjacent end of the baffle sheet is selected so that at the end of the baffle sheet the magnetic field defines a magnetic zone in which is retained a bead-shaped supply of developer powder from which the magnet drum makes up its brush replenishment.
  • the arrangement of the present invention exhibits numerous advantages. It has been found that by throwing the developer powder onto the baffle sheet the developer powder is subjected to pulses affecting the adhesion of color particles to carrier particles and leading to a condition between carrier and pigment particles that improves the developer powder sensitivity to development even under low incitement.
  • baffle sheet is upwardly inclined toward the magnet drum, and the developer powder is thrown on an intermediate region or respectively a lower region of the upper surface of the baffle sheet.
  • This ensures the effective establishment of the elongate reservoir zone.
  • the end portion of the baffle sheet extending toward the pump is bent and dips into the supply of developer powder, in thereby providing a mist barrier at the lower surface of the baffle sheet, for drum-shaped material configuration.
  • the at least one pump a hollow cone adapted to be driven about its center axis, the cone dipping, at its bottom end, into a supply of developer powder and being adapted to convey the developer powder along its inner surface toward its upper edge.
  • the developer powder will be subjected to surface stresses that influence the individual particles in a manner so as to improve the sensitivity of the developer powder when subjecting the same to even small effects of a latent electrostatic image.
  • This effect is believed to be particularly important because the special type of pump introduces thereby a functional effect into the development. Even if this were not the case, there still remains the triboelectric influence which occurs automatically whereby the here described pump has the further advantage of feeding and replenishing the magnet drum across the whole axial length thereof from its virtually spatially restricted location likewise allowing a corresponding location of replenishment material, and this effect is further enhanced by the so-called pre-brush, i.e. the accumulation of material on the baffle plate.
  • the center axis of the hollow cone and the drive shaft thereof are inclined so that the upper circumference at the side facing the baffle sheet is disposed lower than the other circumference.
  • the inner surface of the hollow cone is provided with profilings.
  • a profiling may consist of a spiral thread that is machined in the direction of rotation.
  • the magnet drum consists of a rotary magnet system of axially extending magnets of alternately opposite polarities rotating within a stationary tubular sleeve made of a non-magnetizable material, and the stationary tubular sleeve mounts a stripper for removing the magnetic brush material of the developer powder, the stripper being disposed at an apex facing away from the optionally cylindrical recording material.
  • stationary tubular sleeves are per se conventional, the present embodiment is suitable within the scope of the present invention.
  • the driven hollow cone dips into the sump of a hopper-shaped supply reservoir.
  • the general casing must be of a hopper-shaped configuration.
  • the hollow cone with means for enhancing the introduction of developer powder.
  • an annular magnet in the lower portion of the hollow cone that dips into the supply. This annular magnet attracts the developer powder and is advantageous when the hollow cone rotates insofar as the developer powder will be collected in an annular region from which the powder readily migrates upwardly, due to the rotation.
  • the annular magnet is arranged at the lower surface of a spider interconnecting the hollow cone with a drive shaft.
  • the outer diameter of the annular magnet is smaller than the inner diameter of the hollow cone in the same plane.
  • the lower edge of the hollow cone itself may likewise be provided with a particularly internally recessed annular magnet.
  • a screw conveyor is arranged within a supply reservoir including a trough corresponding to the width of the copying material, and the screw conveyor includes conveyor elements of a configuration for supplying developer powder to the at least one hollow cone. Even when the supply reservoir collects material discharged over the whole length of the magnet drum, this material will be supplied to the pump having simultaneously the function of a mixing element.
  • FIG. 1 is a cross-sectional elevational view of a preferred embodiment of the present invention
  • FIG. 2 is a view similar to FIG. 1 of another embodiment
  • FIG. 3 is a sectional view along the line III--III of FIG. 2;
  • FIG. 4 is a fragmentary view showing a particular embodiment of the pump used
  • FIG. 5 is a view similar to FIG. 4 of another embodiment.
  • FIG. 6 is a schematical fragmentary sectional view of a copying machine with the developing apparatus, as seen from the right hand side in FIG. 1.
  • FIGS. 1 and 2 are fragmentary views of a copying machine whereby a substantial member thereof, i.e. a drum for bearing the latent image upon exposure is only partially shown.
  • a drum 1 that is coated e.g. with a selenium layer that may likewise be enriched with other materials.
  • a latent image is generated on this layer which may be termed likewise "material”.
  • This latent image is then developed by the described developing apparatus.
  • particles of pigment are deposited on the material or respectively on the drum 1 in correspondence with attraction forces, and the problem is to feed these pigment particles in a favorable manner.
  • a magnet drum 2 that rotates within a tubular sleeve 3.
  • the magnet drum 2 includes about its circumference several poles of alternating North and South polarities, as shown in FIG. 1 by poles 4 to 9.
  • the tubular sleeve 3 of a non-magnetizable material is stationary.
  • the magnet drum 2 is rotated e.g. in the direction of the arrow 11, in order to obtain the required relative movement.
  • a magnetic powder brush indicated by 12 moves thereby along the stationary tubular sleeve 3 against the direction of rotation 11, from the bottom to the top of the tubular sleeve.
  • the developer powder of carrier and pigment particles is fed to the tubular sleeve 3 from below.
  • a baffle sheet 13 approaching the lower apex of the tubular sleeve 3 and extending beyond this lower apex and having at its free end an upwardly bent portion 14.
  • This bent portion 14 defines a stop for accumulated material.
  • the spacing of the baffle sheet from the magnet drum or respectively the tubular sleeve is so small that the magnetic field of the magnet drum is effective likewise ahead of the bent portion 14 and acts on magnetizable developer powder.
  • means 15 in the form of a pump consisting of a hollow cone 16.
  • This hollow cone dips, by its bottom edge 17, into a supply 18 of developer powder within a casing 19 of the developing apparatus.
  • the hollow cone is provided internally with a spider 20 and a drive shaft 21 mounting at its end extending from the casing 19 a drive means 22 such as optionally a pulley for rotating the hollow cone 16.
  • the arms of the spider 20 may consist of vanes.
  • the hollow cone 16 includes an upwardly enlarged wall member at the inner surface of which is urged upwardly the material entering through the bottom opening.
  • the inner surface 23 may be provided with profilings such as one or several spiral threads 24 for enhancing the circulating movement.
  • the upwardly conveyed developer powder is projected from the upper edge 25 of the hollow cone and impinges onto the baffle sheet 13 at the side of the magnet drum 2 disposed between the drive shaft 21 and the cylinder drum 1.
  • the developer powder hits the baffle sheet 13 substantially in an intermediate height thereof, for storing in this manner a supply bead 26 from which the magnet drum derives its brush supply.
  • this bead defines, together with the slope of the baffle sheet 13 with respect to the upper height of the edge 25 of the hollow cone 16, an important element for uniform supply along its whole axial length of a magnet drum of a predetermined format. It should be mentioned explicitly that several conveyor means 15 of this type may be provided.
  • the combination with the radial ejection of the developer powder, in influencing the adhesion forces between pigment and carrier particles, and the chute-type baffle sheet already within the range of a magnetic field to establish a supply and up to the region of the direct removal of magnetic brush material ensures thereby surprisingly a magnet drum feed and the replenishment by a concentrated section with respect to the length of a magnet drum or respectively a magnet drum section, in providing the advantage that replenishment need only be supplied to the concentrated section.
  • the stationary tubular sleeve 3 is engaged, beyond the apex of the upper region with respect to the brush rotation, by a stripper 27 by which the magnetic brush 12 or respectively the material defining this brush is being removed in the manner of a chute and is transported back into the supply 18. It is thereby preferred that the stripper which may be integral with the stationary tubular sleeve 3 extends up to a region into which opens likewise a feed conduit 28 supplied from a make-up reservoir 29.
  • the discharge and supply device which is coupled to drive means for also the drum 1 is generally designated by the reference numeral 30 and rotates in the direction indicated by the arrow. This device may consist e.g. of a floc-carrying drum.
  • the baffle sheet 13 includes at its end facing the means 15 a substantially vertically downwardly depending portion 31 which preferably dips into the supply 18 of developer powder.
  • mist barrier that is closed automatically by this supply.
  • This mist barrier mutually separates two spaces.
  • the means 15 In the one space is disposed the means 15 with the trajectory of the developing powder onto the baffle plate 13, delimited by the bead-shaped stop ahead of the end 14 of the baffle sheet, and on the other side at most material thrown off the developer powder brush 12 drops along the casing wall 32 into the supply 18 whereby is safely prevented any whirling up by the means 15.
  • the casing 19 may define a hopper converging downwardly on all sides below the means 15.
  • the casing 19 includes a bottom wall or respectively a trough 33 extending parallel of the magnet drum 2, and a worm screw 34 is movable above this bottom wall.
  • This worm screw 34 includes conveyor elements 35, 36 that are coaxial with the curvature of the bottom wall 33.
  • the conveyor elements 35, 36 may consist of vanes, spiral threads or spiral thread sections of opposite feed directions on both sides of the drive shaft 21 so that material dropping off the baffle sheet 13 or returned into the supply 18 underneath the baffle sheet will be stirred up and transported toward the center below the conveyor and mixing means 15 which as described above not only effects the upward transport but likewise influences favorably the complex developer powder prior to the distribution thereof across the whole width.
  • the spider 20 interconnecting the hollow cone 16 with the drive shaft 21 is provided, at its bottom surface, with an annular magnet 37 for attracting developer powder from the developer powder supply into the bottom opening 38 of the hollow cone 16, in defining its own brush 39.
  • this brush is projected against the inner surface of the conical wall and migrates upwardly along this wall.
  • the spider 20 is provided with a hub 40 to which is attached the annular magnet. It is likewise possible to attach an annular magnet to the inner surface of the hollow cone 16 at the lower edge, as shown in broken lines at 41.
  • FIG. 6 illustrates a casing 42 with two side plates 43, 44.
  • the assembly is mounted between these two side plates. It may be seen that the drum 1 engages the side plate 43 by a trunnion 45 and is journalled in the side plate 44 at the opposite side by means of a projecting shaft 46.
  • the shaft 46 extends into a gear transmission 47 driven by the motor 48.
  • the developer casing 19 is supported against the side plates by brackets 49, 50 respectively. From this casing extends laterally the shaft 51 of the magnet drum 2 into the gear transmission 47, whereby this shaft is journalled in the side plate 44. At the opposite end of the magnet drum, the shaft is journalled in the casing 19 at 52.
  • the shaft 53 of the discharge and supply device 30 extends through the side plate 44 into the transmission 47.
  • This shaft is journalled in an extension of the housing 19 whereby the bearing at the opposite side is indicated by the reference numeral 54.
  • the drive means 22 consists of a disc that is connected by a gear unit 55 to a motor 56 which is mounted on the side plate 44.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Magnetic Brush Developing In Electrophotography (AREA)
  • Dry Development In Electrophotography (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
  • Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)
  • Holo Graphy (AREA)
US05/832,670 1976-09-24 1977-09-12 Feeding device for supplying developer powder to a magnetic drum Expired - Lifetime US4144839A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2643032 1976-09-24
DE2643032A DE2643032C3 (de) 1976-09-24 1976-09-24 Magnetbürsten-Entwicklungsvorrichtung

Publications (1)

Publication Number Publication Date
US4144839A true US4144839A (en) 1979-03-20

Family

ID=5988766

Family Applications (1)

Application Number Title Priority Date Filing Date
US05/832,670 Expired - Lifetime US4144839A (en) 1976-09-24 1977-09-12 Feeding device for supplying developer powder to a magnetic drum

Country Status (15)

Country Link
US (1) US4144839A (de)
JP (1) JPS5360238A (de)
AU (1) AU512392B2 (de)
BE (1) BE858870A (de)
BR (1) BR7706372A (de)
CH (1) CH620529A5 (de)
DE (1) DE2643032C3 (de)
DK (1) DK416877A (de)
ES (1) ES462570A1 (de)
FR (1) FR2365827A1 (de)
GB (1) GB1561931A (de)
IT (1) IT1087459B (de)
NL (1) NL7710252A (de)
NO (1) NO143041C (de)
SE (1) SE7709718L (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0079223A2 (de) * 1981-11-06 1983-05-18 Xerox Corporation Vorrichtung und Verfahren zum Entfernen von Tonerteilchen
US20050019064A1 (en) * 2000-07-14 2005-01-27 Masumi Sato Color image forming apparatus, and toner replenishing apparatus

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5675662A (en) * 1979-11-26 1981-06-22 Hitachi Ltd Operating method of electrophotographic apparatus
RU2581594C2 (ru) * 2014-10-06 2016-04-20 Евгений Николаевич Коптяев Улучшенный понижающий преобразователь частоты

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3640248A (en) * 1969-06-04 1972-02-08 Xerox Corp Electrostatic magnetic developing apparatus
US3828728A (en) * 1971-11-11 1974-08-13 Xerox Corp Xerographic development system
US3881446A (en) * 1973-01-25 1975-05-06 Minolta Camera Kk Magnetic brush developing apparatus

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1568681A (de) * 1967-06-16 1969-05-23
US3866575A (en) * 1971-09-06 1975-02-18 Canon Kk Magnet roll developing device
US3968773A (en) * 1972-05-22 1976-07-13 Xerox Corporation Magnetic brush developing apparatus
JPS50155235A (de) * 1974-06-04 1975-12-15

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3640248A (en) * 1969-06-04 1972-02-08 Xerox Corp Electrostatic magnetic developing apparatus
US3828728A (en) * 1971-11-11 1974-08-13 Xerox Corp Xerographic development system
US3881446A (en) * 1973-01-25 1975-05-06 Minolta Camera Kk Magnetic brush developing apparatus

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
IBM Technical Disclosure Bulletin, Buckley et al., "Magnetic Brush Developer," vol. 20, No. 1 (Jun. 1977) p. 261. *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0079223A2 (de) * 1981-11-06 1983-05-18 Xerox Corporation Vorrichtung und Verfahren zum Entfernen von Tonerteilchen
EP0079223A3 (en) * 1981-11-06 1983-11-30 Xerox Corporation Apparatus and process for removal of toner particles
US20050019064A1 (en) * 2000-07-14 2005-01-27 Masumi Sato Color image forming apparatus, and toner replenishing apparatus
US7212764B2 (en) * 2000-07-14 2007-05-01 Ricoh Company, Ltd. Color image forming apparatus, and toner replenishing apparatus
US20070177902A1 (en) * 2000-07-14 2007-08-02 Masumi Sato Color image forming apparatus, and toner replenishing apparatus
US7457561B2 (en) 2000-07-14 2008-11-25 Ricoh Company, Ltd. Color image forming apparatus, and toner replenishing apparatus

Also Published As

Publication number Publication date
DE2643032B2 (de) 1978-09-28
NO773170L (no) 1978-03-29
BR7706372A (pt) 1978-05-09
DK416877A (da) 1978-03-25
JPS5360238A (en) 1978-05-30
DE2643032C3 (de) 1979-05-31
DE2643032A1 (de) 1978-03-30
NL7710252A (nl) 1978-03-29
AU512392B2 (en) 1980-10-09
ES462570A1 (es) 1978-07-01
BE858870A (fr) 1978-01-16
CH620529A5 (de) 1980-11-28
IT1087459B (it) 1985-06-04
AU2881477A (en) 1979-03-22
GB1561931A (en) 1980-03-05
FR2365827A1 (fr) 1978-04-21
NO143041C (no) 1980-12-03
NO143041B (no) 1980-08-25
SE7709718L (sv) 1978-03-25

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